A concrete float, float assembly, float adapter and interface, and vibration apparatus and methods are described. A vibration assembly has at least first and second interface components, and for example one interface component can join with an interface component on a pivot assembly and another interface component can join with an interface component on a finishing tool. An interface such as may be included in a quick attach/release configuration may be integrated on vibration apparatus and/or on a pivot assembly for quick attach/release of a joining component. A vibration assembly may include a load transmission or transfer component for transferring a load through the vibration assembly. A pivot assembly may include first and second interface components.

A concrete float, float assembly, float adapter and interface, and vibration apparatus and methods are described. A vibration assembly has at least first and second interface components, and for example one interface component can join with an interface component on a pivot assembly and another interface component can join with an interface component on a finishing tool. An interface such as may be included in a quick attach/release configuration may be integrated on vibration apparatus and/or on a pivot assembly for quick attach/release of a joining component. A vibration assembly may include a load transmission or transfer component for transferring a load through the vibration assembly. A pivot assembly may include first and second interface components.

There is provided a hole machining method, using a tap tool which rotates about an axis of rotation and which includes a threaded part which has a blade for machining a threaded groove in a pilot hole, and a non-engaging part which forms a space between itself and the pilot hole in a cross-sectional view in which the axis of rotation and a center axis of the pilot hole are aligned, the method including the steps of machining a threaded groove by rotating the tap tool and advancing it toward a workpiece side in a first state in which the center axis and the axis of rotation are aligned, rotating the tap tool about the axis of rotation and moving the tap tool in an interior of the pilot hole toward the non-engaging part side in a direction orthogonal to the axis of rotation to transition the tap tool from the first state to a second state in which engagement between the threaded part and the threaded groove is released, and retracting the tap tool from the threaded hole.

A method of producing a rotationally orientated thread starting at a desired angular position and suitable for mass production is provided. The method is particularly suitable for improving the angular positioning of spark plugs in car engines. The method involves measuring precisely the length (L) of the tool (13) and the distance, at a particular angular position, of a full thread form (14) of the thread to the tip, so that its start position at the tip can be calculated. Using that distance as an offset of the length of the tool reported to the CNC machine, and starting from its reference position, it commences producing the thread (12) in the bore (11) at the desired angular position of the bore (11).

A method of producing a rotationally orientated thread starting at a desired angular position and suitable for mass production is provided. The method is particularly suitable for improving the angular positioning of spark plugs in car engines. The method involves measuring precisely the length (L) of the tool (13) and the distance, at a particular angular position, of a full thread form (14) of the thread to the tip, so that its start position at the tip can be calculated. Using that distance as an offset of the length of the tool reported to the CNC machine, and starting from its reference position, it commences producing the thread (12) in the bore (11) at the desired angular position of the bore (11).